#include<cstdio>//uncle-lu
#include<algorithm>
template<class T>void read(T &x)
{
	x=0;int f=0;char ch=getchar();
	while(ch<'0'||ch>'9') { f|=(ch=='-'); ch=getchar(); }
	while(ch<='9'&&ch>='0') { x=(x<<1)+(x<<3)+(ch^48); ch=getchar(); }
	x = f ? -x : x;
	return ;
}

int line[100010];
int sta1[100010], sta2[100010], top1, top2;

int main()
{
	while(~scanf("%d",&n))
	{
		top1 = 0; top2 = 0;
		for (int i = 1; i <= n; i++)
			read(line[n-i+1]);
		for (int i = 1; i <= n; i++) 
		{
			while()
		}
	}
	return 0;
}
